Sony WRT-810A User manual

SONY.
UHF SYNTHESIZED WIRELESS MICROPHONE
WRT-810A
SERVICE MANUAL
US Model

WRT-810A
3369
Notice for customers in the U.S.A.
Use of Sony wireless devices is regulated by the Federal Communica-
tions Commission as described in Part 74 subpart H of the FCC
regulations and users authorized thereby are required to obtain an
appropriate license.
You are cautioned that any changes or modifications not expressly
approved in this manual could void your authority to operate this
equipment.
TABLE OF CONTENTS
1. OPERATION
1-1. Specifications Cee c cree ce nnc nn ee ent ecencccnenecsusvovccsccucccecncce dul
12.
Overview
cccceterscscessreccsscccccecassessssscesssscoseerscasceces
1-2
1-3. Parts Identification Comoe nee e race ence seseesevessncucessccecce 13
14. Inserting Batteries --:-::s:esssssecssssesscessveneseceseoerecees 1-3
1-5.
Changing
the
Channel
Selection
cesr:ssssceceeceseseees
14
146.
Changing
the
Input
Attenuation
Setting
«+--+
1-5
1-7. Using the Transmitter --reesscsccssesccccscccsscsccescnsceees 16
1-8. Channels and Carrier Frequencies --+rrssscccseereeeees 16
2. SERVICE INFROMATION
Q-1.
Disassembly
--sscccccesssssceceeesssscessscsssessessscesnseesseeees
22.
Precautions
on
Reassembly
23.
Note
on
Parts
Replacement
Oe
necccccsvocveecccccccascceces
2-7
2-31.
SBX1608,
E7PROM
(1C203,
CP302)
RePlaceMent
cerrerecseeessceeeccnseececeesssessecesseuseeeoees
2-7
2-4.
Precautions
on
Chip
Parts
Replacement
---++-++--:
27
3.
ELECTRICAL
ADJUSTMENTS
3-1.
Equipment
and
Tools
3-2.
Adjustment
<rrerecercersesseteeeceeeecenssesaceesecseeeevsceneeeees
3-2-1.
+5
V
(Vcc)
Regulated
Voltage
Adjustment
--
34
3-2-2.
Carrier
Frequency
Adjustment
-s-+++:++e++ssseeree
34
3-23,
Reference
Flequency
Deviation
Adjustment
---
3-5
3-24.
Maximum
Frequency
Deviation
Adjustment
---
3-5
3-25,
Distortion
Ratio
Check
B-26,
SAN
Check
«scerssccscscacccescsconsssssccsseccscscns
3-2-7,
Frequency
Characteristics
Check
-++++++++++s1++
3-7
3-28.
RF
Power
Output
Check
<s:esscesescsseessesceeseeees
3-7
3-2-9.
Tone
Signal
Check
-s++::cesssssssssesssscssscecssseesseee
38
3-2-10.
Spurious
Emissions
Check
-s-+sesssssssssssseeseseeees
38
3-2-11.
Occupied
Band
Width
Check
crsrsssssssesseeeeee
39
4.
SEMICONDUCTOR
PIN
ASSIGNMENTS
--.---------
41
5.
BLOCK
DIAGRAM,
BOARD
LAYOUT,
SCHEMATIC
DIAGRAM
AND
LEVEL
DIAGRAM
51. Block Diagram
5-2. Board Layout
5-3. Schematic Diagram
6. SPARE PARTS
SECTION 1
OPERATION
1-1. SPECIFICATIONS
Transmitter and Modulator Section
Oscillator Crystal controlled PLL synthesizer
Carrier frequencies 94 settings at 125-kHz intervals
WRT-810A (64): 770.125 to 781.875 MHz
WRT-810A (66): 782.125 to 793.875 MHz
WRT-810A (68): 794.125 to 805.875 MHz i
Tone signal 32.768 kHz
Type of emission 110KF3E
RF power output 10 mW/2.5 mW, selectable (50 ohms)
Frequency stability Within +0.005% °
Less than 2.5 pW
1/4 wavelength wire
Spurious radiation
Type of antenna
Pre-emphasis 50 us
Reference deviation +5 kHz
Maximum deviation +40 kHz
Maximum modulation frequency
15 kHz
100 Hz to 13 kHz
More than 60 dB (A-weighted, with reference
deviation at WRR-820A/840A)
Less than 1.5% (with reference deviation)
0 to 21 dB, variable in 3-dB steps
(21 dB attenuation)
Frequency response
Signai-to-noise ratio
Audio distortion
Audio attenuator
Maximum input sound pressure level
151 dB SPL
Microphone unit Uni-directional dynamic type
Power Section
Power requirements 3 V DC (two L40 (LR6) alkaline batteries)
Battery life About 8 hours at 25°C or 77°F (with Sony AM3
(LR6) alkaline batteries )
Current consumption Less than 170 mA (at 3 V)
General
Operating temperature
0°C to 50°C (32°F to 122 °F)
Storage
temperature
—
30°C
to
+60°C
(—
22°F
to
+140°F)
Dimensions
48
X
238
mm
(maximum
dia./length)
(1/6
X
9%
inches)
Weight
About
300
g
(including
batteries)
(10.5
02)
Accessories supplied Microphone holder (1)
Stand adaptor PF '/, to NS ‘/. (1)
6-1.
Exploded
View
and
Parts
List
-+---+-+ssssssecessssees
6-1
6-2.
Electrical
Parts
List
-+ss+s++sssssscssecccscessesessensscscnces
6-3
6-3.
Accessories
Supplied
tree
eee
ens
rccencesecrecersesscncnsesenees
65
1-1
rato ait Sa Ad Soke:

Frequency band
1-2. OVERVIEW
The WRT-810A is transmitter for an 800 MHz
band UHF synthesized wireless microphone system to be used for
broadcast or movie production purposes. The other system compo-
nents include the AN-820A UHF antenna, the WD-820A UHF antenna
divider, and the WRR-820A/840A UHF synthesized diversity tuner.
TV
channel Frequency (MHz)
770.125 — 775.875
WRT-810A(64)
776.125 — 781.875 WRT-820A(64)
a 782.125 — 787.875
za 794.125 — 799.875
a 800.125 — 805.875
Features
Easy selection of 94 channels
With its sophisticated phase locked loop (PLL) circuit, the unit can
operate on any one of 94 carrier frequencies in a 12 MHz frequency
band for each model, selected by a simple button operation.
Each channel is identified by a number consisting of a 2-digit TV
channel number and a 2-digit wireless microphone channel number
(example: 68-23).
See “Channels and Carrier Frequencies” on page 1-6 for more details.
WRT-810A(66)
WRT-820A(66)
WRT-810A(68)
WRT-820A(68)
Operation powered by widely available batteries
The built-in DC-DC converter allows stable operation, for up to eight
hours continuously, with just two L40 (LR6) alkaline batteries.
CPU and LCD for coordinated operation control
The built-in CPU controls the unit operation including the PLL circuit
function. The LCD shows the current channel number, the residual
battery power, the input attenuation setting, the AF input level and the
RF output.
Saved channel and input attenuation settings
The unit stores the channel and the input attenuation settings when it is
turned off. The saved settings are retained even if the batteries are
removed. Therefore, when using the unit next time, you need not
make the same settings again.
1-2
| WRT-810A
The microphone and tuners are classified by frequency
band. See the table on the next page.
A 12 MHz frequency band (or two consecutive-numbered TV channels)
is assigned to each microphone and tuner model. To
indicate the assigned frequency bands, the parenthesized numbers
following the model names in the table show the smaller of the assigned
TV channel numbers. In building up a UHF wireless microphone
system, be sure to combine a microphone and a tuner
having the same TV channel number.
WRR-820A(64)
WRR-840A(64)
WRR-820A(66)
AN-820A WD-820A
WRR-840A(66)
WRR-820A(68)
WRR-840A(68)
Highly reliable electronic attenuator
The built-in input level attenuator is adjustable in the range of 0 to 21
dB in 3 dB steps. It reduces signal distortion when an excessively
strong input signal is received.
Handy audio input switch
You can use the AF switch of the microphone as a handy audio cluding
input ON/OFF switch.
RF carrier with tone signal
The unit transmits the RF carrier accompanied by a tone signal,
enabling the tuner with a tone squelch circuit to take out only the target
audio signal received.
Wide dynamic range and low noise
The compander (compressor/expander) system enables transmission
over a wide dynamic range with minimum noise.

WRT-810A
1-3. PARTS IDENTIFICATION
Cage
Reduces noise caused
by the wind. ?
POWER switch
Setting this switch to ON puts the unit in transmission mode,
recalling the channel selection and the input attenuation setting.
Setting this switch to CFF turns off the unit, saving the
channel selection and the input attenuation setting.
RF power output select
; switch
Selects RF power output
2.5 mW or 10 mW.
; 2.5 mW: Suitable for a
working range of up to
30 m (98 feet).
10 mW: Suitable fora |
~
AF switch
Switches on and
oft the audio
input. Battery
holder
Grip
working range exceeding
30 m (98 feet).
Wire antenna
ely
Display section
AF indicator.
The indicator appears when the input
audio signal level is higher than needed
to obtain the reference deviation.
TVIATT indicator
indicates the current TV channel selection
in channe! display or channel set mode,
or the current input attenuation setting in
decibels in attenuation display/set mode.
+/~ buttons —
Use these buttons to increment or
decrement the channel selection in
channel set mode or the input attenuation
setting in attenuation display/set mode.
+/-/SET buttons
+ - ser
Bw
Use a ball-point pen or simitar instrument
to press these buttons.
RF indicator
The indicator appears when the RF carrier
is being transmitted.
CH indicator ;
indicates the current wireless microhpne
channel selection in channel display or
channel set mode. When the unit is in
attenuation display/set mode, this
indicator shows “- —".*
BATT indicator
i] The batteries are in good condition
(a): The residual battery power is below
the 50% level.
: The batteries are exhausted.
Replace them.
(When this indicator appears,
the whole display starts flashing.)
SET button
Use this button to enter channel set or
attenuation dispiay/set mode.
* The example show TV channel display on the WRT-810A (68).
1-4.
INSERTING
BATTERIES
¢
s
* lal.
*+-——— Two L40 (LR6)
alkaline batteries
Grip
+ Be sure to turn the POWER switch off before replacing the batteries.
« When the unit is turned on with batteries which are exhausted, the
BATT indicator displayed may reflect their temporarily recovered °
power which will reduce very quickly. Before starting extended
operation, replace the batteries in the unit even if the BATT indicator
shows fz] or [=]
Notes on batteries
Be sure to insert the batteries with the correct polarity.
Do not pair different types of battery.
Always replace the two batteries together.
The batteries are not rechargeable.
When keeping the unit out of use for extended periods of time,
remove the batteries to avoid leakage.
Should the batteries be found to have leaked in the unit, replace them
with new ones after carefully wiping the leakage from the battery
hoider or case.

1-5. CHANGING THE CHANNEL SELECTION
—
1 While pressing the SET button, set the POWER switch to ON
to enter channel set mode.
The current channel selection will appear on the display.
AF RF BATT
“ ae
TV/ATT CH
The example show TV channel display on the WRT-810A (68).
2 Press the + button to increment the current channel selection
or the — button to decrement it.
AF RF
wm
TV/ATT CH
BATT
POWER AF
If you keep either button pressed, the channel selection will be
incremented or decremented successively.
The setting will cycle the channel number from 68-01 through
69-47.
The
example
show
TV
channel
display
on
the
WRT-810A
(68).
1-4
WRT-810A
3 Set the POWER switch to OFF to save the selected channel
number along with the current input attenuation setting.
AF RF SATT
TV/ATT CH
* The unit cannot transmit in channel set mode.
* Make sure that the channel! selected is the same as that selected on
the WRR-820A/840A unit used in the same system.
* Depending on the noise or interference conditions, the selectable
channels may not necessarily all be usable. !f necessary, you can
determine the usable channels by stepping the channel selection
through a number of channels on the tuner with the transmitter
set to OFF. Those channels on which the RF indicator of
the tuner does not light are usable. .
If there is a TV broadcasting station nearby, to avoid possible
interference
with
broadcasing,
do
not
use
that
station's
channel.
The
unit
may
not
operate
correctly
if it
is
turned
on
again
immediately
after
turning
off
the
power
while
in
channel
set
mode. Pause
for
a
few
seconds or more before turning on the power again.